1. Field of the Invention
The invention relates to a corona-generating device for electrophotographic printer or copier devices including a wire shaped electrode arranged at a distance from a photoconductor.
2. Description of the Prior Art
Corona-generating devices are utilized for numerous purposes in electrophotographic printer or copier devices. For example, for charging the photoconductor, for transferring a developing image onto the continuous web paper in the transfer station, for removing background particles from a developed, latent electrostatic image and for cleaning the photoconductor drum by neutralizing the charge on the remaining toner particles.
As may be derived from U.S. Pat. No. 2,856,533 or from German No. OS 2 424 835, such corona-generating devices are generally composed of at least one wire-shaped electrode, what is referred to as the corotron wire, which is surrounded by a shielding.
Although these corona-generating devices are capable of effecting a uniform electrostatic charge on the surface provided therefore, dust particles, toner particles or other particles can collect on or around the corotron wire and its shielding and can produce a non-uniform generation of the corona current along the length of the corotron wire. With this in mind, German No. OS 24 24 835 discloses that cleaning apparatus be provided in corona-generating devices.
It is also standard to engage the corotron wire extending over the full length of an intermediate carrier (photoconductive drum) at stationary end points. The corotron wire in the transfer station stretched freely over the photoconductive drum when printing paper sheets which are narrower than the photoconductor contaminates and damages the coatings of the photoconductor in those regions not covered by paper.